Oxidative stress in stationary-phase cultures

ABSTRACT: Background: As carbon sources are exhausted, Saccharomyces cerevisiae cells exhibit reduced metabolic activity and cultures enter stationary phase. We asked whether cells in stationary-phase cultures respond to additional stress at the level of transcript abundance. Results: Microarrays were used to quantify changes in transcript abundance in cells from stationary-phase cultures. In response to oxidative stress, more than 800 mRNAs increased within 1 minute. A significant number of these mRNAs encode proteins involved in stress responses. We tested whether mRNA increases were due to new transcription, rapid poly-adenylation of message (which would not be detected by microarrays), or potential release of mature mRNA sequestered in the cell but insoluble during RNA isolation. Examination of the response to oxidative stress in an RNA polymerase II mutant, rpb1-1 suggested new transcription was not required. Quantitative RT-PCR analysis of a subset of these transcripts further suggested that essentially all isolated transcripts were polyadenylated. In contrast, over 1000 transcripts increased after protease treatment of cell-free lysates from stationary-phase but not exponentially growing cultures. We also determined that oxidative stress and temperature upshift led to the release of different transcripts, suggesting that mRNA release is stress specific. Conclusions: A large number of mRNAs are sequestered in a protease-labile, rapidly releasable form in cells in stationary-phase cultures but not exponentially growing cultures. The differences between mRNAs released by protease treatment and those observed with oxidative stress and temperature upshift, suggest different stresses cause the release of different transcripts. We hypothesize that P-bodies are involved in this sequestration. Keywords: stress response

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE3729 | GEO | 2005/12/03

SECONDARY ACCESSION(S): PRJNA93889

REPOSITORIES: GEO